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MIMM 324 > Orthomyxoviruses > Flashcards

Orthomyxoviruses Flashcards

(51 cards)

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1
Q

true or false: influenza viruses have almost an unlimited amount of serotypes

A

true

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2
Q

true or false: influenza is an endemic disease

A

false it is an epidemic disease
worst months: February

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3
Q

True or false: influenza is a pandemic disease

A

true

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4
Q

when did asian flu was a thing

A

in 1957 in usa, rhode island
girl scouts fucked up

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5
Q

What does Flu do

A

-it affects and kills cells of our respiratory tract
-wipes out mucocilary defenses

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6
Q

What is a part of the structure of influenza?

A

-HA: hemagglutinin 16 completely distinct gene types A
-NA: neuraminidase 9 completely distinct gene types A
-NS1: major non structural protein
-Helical nucleocapsid
-lipid bi layer membrane
-polymerase: 3 peoteins
-M1 protein: matrix protein

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7
Q

true or false: NS1 is expressed in influenza infected cells

A

true

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8
Q

What are the three groups of influenza

A

A, B and C which is based on the nucleoprotein type

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9
Q

True or false: influenza viruses from different groups can recombine

A

false: they can’t

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10
Q

which type of influenza viruse4s can infect only humans

A

B and C

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11
Q

Which type of influenza virus can infect all mammalian and avian species

A

A

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12
Q

True or false: only C influenza viruses can cause pandemics

A

false it is A

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13
Q

True or false: there is no antigenic cross-reactivity between different hemagglutinin and neuraminidase types

A

true

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14
Q

first influenza pandemic

A

h3n2

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15
Q

spanish flu name of strain and when did it started

A

1918 H1N1

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16
Q

First isolation of influenza

A

in 1933 H1N1

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17
Q

Asian flu 2

A

H2N2 1957

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18
Q

Hong kong flu

A

h3n2 1967 and in 1976 there was h1n1 too

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19
Q

MEXICAN FLU

A

h1n1 2009

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20
Q

how do they make influenza vaccines

A

you take the attenuated donor virus with the new antigenic variant and then you get the attenuated vaccine virus

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21
Q

What is the reservoir for Influenza A viruses

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A

waterfowl basically they have a cloaca where the bladder, the vagina and the colon kinda all merge together

22
Q

Avian influenza true or false: multiplies in cloacae without causing disease

23
Q

True or false: in avian influenza only one strain can exist in individual bird

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A

false, multiple can coexist

24
Q

true or false: there is high level of genetic reassortment in avian influenza

25
True or false: there is little to no selective pressure and little;e genetic change in avian flu
true
26
the 2009 h1n1 was a mix of what?
eurasian flu, h1n1, human h3n2 and avian
27
how did the 1956, 1967 and 2009 pandemic strains arose
-by recombination between human and avian strains possibly within a pig intermediate host - these 3 pandemic strains: human strains with new avian HA+/- NA genes
28
true or false: the 1956 flu pandemic caused the most deaths
false *The 1918 pandemic strain caused far and away the worst human mortality of a known flu pandemic - 10-20 times that of 1956 or 1967
29
why was the 1918 strain unusual
* It commonly killed young and healthy victims * Healthy asymptomatic persons: * Could be struck suddenly * Rendered too feeble to walk within hours * Many would die the next day * Symptoms included: * Cyanosis * Hemoptysis * Later uncontrolled pulmonary hemorrhage and edema - ARDS
30
mortality 1918 flu
Mortality in fast-progressing cases -Primarily from ARDS-like disease -Mortality in slower-progressing cases -Primarily from 2o bacterial pneumonia -Possible neural involvement: - Frequency of psychiatric disorders - Encephalitis lethargica
31
how many people dies from the 1918 flu
100 million worldwide approx 60% of peeps got it and the mortality rate was 2.5-6%
32
WHAT DID THE COMPLETE 1918 INFLUENZA VIRUS CODING SEQUENCE REVEALED?
1) 1918 strain NOT a human/avian recombinant but a PURE avian strain (2) 23 a.a. changes out of 5,672 (3) Sequence did not explain virulence (4) Decision to use reverse genetics to generate a live flu virus with the genome of the 1918 pandemic virus
33
TRUE OR FALSE: THE 1918 strain would not fuck us up rn
FALSE IT WOULD
34
h5n1 1996
in china in chickens a lot of people got sick they killed all them chickens
35
true or false: no evidence of sustained human to human transmission in h7n9
true
36
What would be required to produce a new pandemic strain of influenza that would be as pathogenic as the 1918 strain?
1) HA protein to which humans have little or no immunity (2) HA mutation 1  facile infection of non-respiratory tissues (including macrophages) allowing spread outside lung (3) HA mutation 2  higher affinity oligosaccharide-binding to the human sialyl-6-lactose receptor than to the avian sialyl-3-lactose receptor (4) Polymerase proteins direct facile RNA synthesis in human cells (5) Viral NS1 protein has mutations directing - high level induction of apoptosis - high level inhibition of IFN induction (6) Induction of severe pro-inflammatory effects (cytokine storm) (7) Ability to easily infect humans (8) Ability to cause significant disease in humans (9) Ability to spread easily from humans to humans
37
Difference between h1n1 1918 and current h7N9
does not spread easily human to human
38
what are the drugs attck against flu
neuranimidase inhibitor blocks the cleavage of the receptor aka hemagglutinin and the cell receptor so that no new virion can be released -tamiflu
39
what are the 2 surface proteins of the flu
Na and HA
40
how many mechanisms are there to make express proteins
6
41
true or false: influenza replicates in the nucleus
true Unlike almost all other RNA viruses, influenza virus nucleocapsids are transported to and are transcribed and replicated in the host cell nucleus
42
how does influenza gets in cell
sialic acid receptor and clathrin coated pir
43
which proteins binds to the cell receptor
HA
44
is influenza an rna virus or DNA
- ssRNA
45
true or false: there is a pH conformation change in influenza
true in endosomal membrane
46
Influenza virus RNA transcription:
- PB2 recognizes and binds 5' cap structures found on all eukaryotic mRNAs - PB2 binds to caps of newly-synthesized pre-mRNAs in the cell nucleus - PB1 then acts as a nuclease, cleaving the bound pre-mRNA at an A or G residue 10–13 nt from its 5' cap - This capped RNA fragment, still bound to PB2, is used as primer to copy genome RNA -
47
role of PB1
-PB1 acts as an RNA polymerase
48
Role of PA
- Role of PA is not well understood - Resulting viral mRNAs have heterogeneous sequences for the first 10–13 nt - Flu can thus make capped messenger RNAs even though they do not code for a capping enzyme
49
What does NS1 do
The NS1 protein interferes with polyadenylation of cellular mRNAs NS1 protein is the most abundant viral protein in virus-infected cells NS1 binds to both single- and double-stranded RNA and to two host cell proteins: (1) cleavage and polyadenylation specificity factor (CPSF) (2) poly(A)-binding protein II (PABII) Binding of NS1 to these proteins inhibits normal 3' end cleavage and polyadenylation of cellular mRNAs Polyadenylation of viral mRNAs occurs by a distinct mechanism and does not depend on these cellular enzymes
50
Cap-binding and endonuclease activities of the influenza PB2 and PB1 proteins leads to
Cap-binding and endonuclease activities of the influenza PB2 and PB1 proteins leads to degradation of cellular pre-mRNAs in virus- infected cells As a combined result of interference with 3' end processing and 5’ end cleavage - most cellular pre-mRNAs are degraded in the nucleus - cellular mRNA production and protein synthesis are suppressed
51
Influenza virus and the immune system:
NS1 inhibits activation of the interferon-induced PKR antiviral pathway During influenza virus transcription, some ds-RNAs are inevitably formed Virus infection → interferon production → cells produce double-stranded RNA-dependent protein kinase (PKR) In the presence of ds-RNA, PKR is activated and blocks both cellular and viral protein synthesis

MIMM 324 (26 decks)

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